Electromagnetic relay



July 28, 1931. s. WOODHEAD 1,816,155

ELECTROMAGNETIC RELAY Filed Sept. 9, 1929 InTfilfii- Harry STE r1151] [mourn-wad occupy Patented July 28,1931

UNITED STATES PATENT OFFICE HARRY STANLEY WGODHIAD, 01" LIVERPOOL, ENGLAND, 'ASSIGNGB '10 ASSOCIATED TELEPHONE AND TELEGRAPH GOHPANY, 0] CHICAGO, ILLINOIS, A GOBIBORATION 03 DELAWARE Application fled September 8, 1939, serial I0, 391,148, and in Great Britain Mb 16, 1938.

The present invention relates to electromagnetic rela s and is more particularly concerned wit relays of the moving coil type which are known. to possess greater sensitivity than those in which all the coils are fixed. The advantages of relays of the movin coil type, however, have hitherto been argely offset by the very much greater e ense of these relays and also by the fact ihat theyoccupy a considerably greater space than relays provided with an 11011 armature. Both these points may he of considerable importance in certain situations, for instance in automatic telephone systems, in which a very large number of lays are required. The chlezf object of the present invention is to provide an improved moving coil relay which shall he comparatively inexpensive and also shell the minimum of-space so that enumher of such relays may if desired he mounted compactly together. The attainment of these requirementsis made possible owing to the fact that for the improved relay according to the invention standard parts employed for making relays as hitherto used have loeen utilized to a large extent.

h According to one feature of the invention, 3131' Ml electromagnetic relay of the coiltype the exciting coil is supported on a core whichis substantially parallel to the longer limle of an l..-shapecl yoli'e member, and is supported lay said incniloer, t? e operc ing coil osing attached to a support pivoted on said yoke member.

According to another feature o'l vention, in an electromagnetic relay oi the moving coil type, one of the pole piece comprises a Ill-shaped member secured to yoke, while the other pole piece comprises an extension oi the cylindrical core supporting the exciting coil.

A iurther feature oi the invention is provision of an electromagnetic relay of the moving coil type in which the movable store oi a relayoi the moving iron type is used as a support for the moving coil which is arranged to be capable of substantially: axialmovement with respect to the core an annular air gap about the core.

These features will he better appreciated from the following description of one method of carrying the invention into efiect which should be talgen in conjunction with the accompanying drawings comprising Figs. 1, 2 and 3, in which Fig. 1 is a plan view of the relay assembly, Fig. 2 is an enlarged sectional view taken along the vertical plane including the ax's of the core of the assembly in Fig. l, and Fig. 3 is a view of the D-shaped pole piece. It will he understood, however, that this description is given by way of example only and that various modifications in the constructional details could he made without exceeding the scope of the invention.

Referring 110W to the drawings, the relay shown comprises an exciting coil 10 mounted on a core 1? which is secured to a substantially l.-shapeol yoke 11 by the screw l2 or other suitable means. Secured to the end or the longer limb of the-yoke 11 by a pair of screws 41, and at right-angles to it is o. ill-shaped polepiece 13 better seen in 3, is drilled to accommodatethe movccil and arranged to he centralized in respect to the core 1'? by means of the non- 1 14, which has an outside di ineter equal to the diameter ol the dr' .J coil checl: l5.

Washer lo of magnetic is lternotively riveted to, the

core 17, so that it rests snagnetic washer l i, nd

' er pol apiece of the asse holy.

oi t c screw-23, and ce ries'the cylindrical 1 a suitable groove around its exterior. Tone t coil when position is located the space between the two polepieces l3 end 13 and is capable of slight movement.

"the polepiece l3 and. which is '10 is I energized fine adjustment may be efl'ected by means of the controlling screw 25. The member 18 is made with an extension piece 30, which serves as a contact in the present construction and normall rests against the spring member 31, forming part of the spring assembly. The member 31 may be adjusted by a screw 32 having an insulated point and passing through a comparatively heavy bar member .33, which also forms part of the spring assembly. The contact spring with which the extension 30 engages is indicated .at 34 and may be adjusted by the screw 35 which also passes through the member 33. This member is slotted and a locking screw 36 is provided to maintain the adjustments of screws 32 and 35. I

The ends of the moving coil winding} are connected to separate tags 37, conveniently let into the lower part of member 22, and from thence connection is-ma'de byway of the flexible leads, 38, through suitable grooves in the support to the connection tags 39 of the spring assembly. Thislatter is secured to the yoke member 11 by means of screws 40, and the whole relay ma be readily secured in position on a switc or relay frame by screws passing through suit-' able holes in the shorter'limb of the yoke when the excitin through, a flux is set up in the magnetic circuit of the rela which circuit includes the core 17 the bee piece or yoke 11, polepiece 13, the air ga around pole piece 16 and that pole piece. S operating coil is made of non-magnetic material, the flux created b the energization of coil 10 will have no-e ect on the cup and consequently the armature of the relay. However, when the operating coil is energized, it makes that-coilmagnetic and the inexpeiisive" moving coil relay has "coil, since it is free to move, moves into the air gap wherethemagnetie lines of force are concentrated. This movement, which may be said to be substantially axial with I respect to the core, causes the armature arm 30 to move and thereby close contact ,between spring 31 and contact s ring 34.

automatic telephone circuits where its greater sensitivity will be advantageous.

I claim:

1. In-an-electromagnetic relay, a mag-- netizable core, a magnetizing windin on said core, a yoke member 'lyin paral el to said core and on only one si 6 thereof, a'

D-shaped pole piece secured to one end ,of said yoke member and surrounding one end of said core to form-an air gap around the end of the core, an armature pivoted on said yoke member, a movable coil secured to said armature and projecting into said air gin the energization of said movable coil w ie said magnetizing winding is energized, moving said armature on its pivot.

, 2. In an electromagnetic relay, a magnetizable core, a magnetizing windmg thereon, a cylindrical pole piece forced onto one end of said core, a yoke member lying par,- allel to said core and on only one side thereof, a D-shaped pole piece having a circular aperture therein andsecured to one'end of said yoke member in ition to surround said cylindrical pole piece with any air gap therebetween, a circular washer on said core and of such size as to fit in the circular aperture to hold said D-shapedpole piece eonince'the cup. 22 carrying the i It will be appreciated'there ore that accgr dmg to. the invention a very'com act and en devised, these properties permitting the use of the relay in a number of situations in 

